Fluid line connection



July 10, 1951 F. J. WIEGAND ET AL 2,560,263

` FLUID LINE CONNECTIONS Filed May 9, 1946 I N V EN TORS.

i5 L WIEEAND. W. MEADDR- ATTDRNEY Patented July 10, 1951 Francis J. Wiegand and Duis W. Meador, Ridgewood, N. J., assignors to Wright Aeronautical Corporation, a, corporation of New York Application May 9, 194s, serial No. 668,491

13 Claims.

' l This invention relates to tube or pipe joints and is particularly directed to a tube or pipe joint which is simple to manufacture and assemble and which, when assembled, provides a fluidtight joint capable of providing an effective seal against internal fluid pressures.

Aircraft engines equipped with fuel injection systems -require a large number of fuel lines through which fuel is distributed -to the various engine cylinders. A large number of joints are required in these fuel lines and some of these joints are disposed in relatively inaccessible 1ocations on the engine. Accordingly, it is essential that the joints be relatively simple to assemble and preferably the joints should be somewhat flexible to permit their assembly even though their mating portions are out of alinement. Also, the joints should provide a fluid-tight seal capable of withstanding large internal pressures in order to prevent leakage of fuel. In most prior art joints, it is necessary that care be taken to properly tighten the joint in order that it have the desired sealing characteristics. Accordingly, in the prior art, the effectiveness of the joint seal to a great extent was dependent on the human element involved. However, because of the dangers resulting from leaking fuel lines in aircraft engines, itis quite important that the possibility of fuel lines leaking because of improper assembly be minimized as much as possible.

It is an object of this invention to provide a relatively simple and novel fuel line joint capable of meeting the aforementioned requirements. Although the invention has been designed to provide a joint or fitting for fuel lines on aircraft engines, the invention is obviously not so limited but is of general application.

Qther objects of this invention will become apparent upon reading the annexed detailed description in connection with the drawing in which:

Figure 1 is an axial sectional view through a tube joint embodying the invention;

Figure 2 is an exploded axial sectional view of Figure 1;

Figure '3 is an axial sectional view of a modiflcation; and

Figure 4 is an axialsectional view of a further modification.

.Referring ilrst to Figures 1 and 2, a fuel line comprisinga metallic tube I is provided with a ferrule I 2 braved or otherwise secured to the tube I0 adjacent its one end. The ferrule I2 comprises an external flange or collar portion `I4 and a sleeve I6 extending axially along the tube Ill from said flange u toward the end 'of me tube remote from said flange. The sleeve portion I6 terminates in a plane inclined to the axis of the tube as indicated at I8, thereby reducing the possibility of the thin tube I Il breaking. atits junction with the sleeve I6. The ,tube I0 is to b e coupled to a body member having a chamber or bore 22 for receiving the -tube I0. The body member 20 may comprise an elbow or other connecting member which may have similar coupling provisions at its other end or the body member 20 may comprise part of a fuel nogzle or a fuel distributing member. y

The outer end of the bore -22 is provided with internal threads 24 within which anut 26, disposed about the tube I0, is adapted to be threaded. The nut 26 is arranged to be threadedly secured tov the body member 20 and to -bear against the flange I4 to prevent separation of the tube I0 and body member 20. Also, the nut 26 is designed to have a substantial radial clearance relative to the adjacent portion of the tube I0 so as not to interfere with the flexibility of the tube I0 relative to the body member 20. Means may be provided to limit the extent to which the nut 26 may be tightened. For example, as hereinafter illustrated in Figure 3, the nut may be threaded externally about the body memberwith the end of the body member acting as a stop for the nut. Also the body member may be provided with means other than a threaded nut for engaging the flange I4.

The bottom of the bore 22 is provided with a washer 30 of resilient rubber-like material isy adapted to be disposed between the ange I4 and the shoulder 28. As illustrated in Figure 2, the washer 30 has a free outer diameter slightly larger than the internal diameter of the bore 22 and has a free internal diameter slightly smaller than the external diameter of the tubing I0. At this point, it should be noted that the term free diameter of the washer, as used in the specification and claims, is intended to refer tothe diameter of the washer when no external forces are applied thereto, except of course for the eilect of gravitation. With the Washer 30 having said dimensions, the material of the washer is placed in radial compression between the outer wall of the bore 22 and the tube I0 before the nut 26 is even tightened against the flange I4. With this construction, even thoughthe nut 26 merely grips the threads 24 and is not tightened against the flange I4 or is only tightened by hand against the flange I4, the joint has been found to provide an eilicient hydraulic seal at low as well as at high internal pressures.

The body member 20, if engine, may during engine operation. 'I'his vibration is transmitted to the tube I through the metallic path including the nut 26 and the ferrule I2. In this way, only a small percentage of the vibrations carried by an aircraft be subject to considerable vibration pass through` the sresilient'washerfigand, thereg 1 fore, the vibrations do not wear theY material of:

the washer to reduce the effectiveness of the seal provided thereby. Also, the vibrations are transmitted to the tube I0 through the reinforcing ferrule sleeve I6 thereby minimizing breakage of the tube I6 as a result of the vibrations transmitted thereto. The flange I4-has anv external The center of curvature of-the surface 41 is on the axis of the bore 44 at 46. The tube 40 ls provided with a collar or ferrule 5l! brazed or otherwise secured to the tube 40 adjacent its end. The

ferrule 50 is provided with an external convex spherical surface 52 having a radius of curvature slightly smaller than the radius of curvature of the spherical surface 41'.

The body member 42 is provided with external threads 54 to which a nut 56 is adapted "to be threadedly secured. The nut 56 is provided with an internal concave spherical surface 58 having cylindrical surface co-axial with thetube Ill.l The s external diameter of the flange .I4 is slightly smaller than the adjacent internal diameter of the bore 22 to provider a small clearance therebetween. The clearance between the flange I4 and the body member v20 is small enough to prevent extrusion of the rubber-like material of the washer 30 therethrough by the hydraulic pressure within the tube I0. Accordingly, 'the magnitude of the clearance depends on the particularf I0 and the body member 20, thereby permitting insertion of the tube I0 within the bore 22 even though the tube I0 and bore 22 are slightly out of line.y The magnitude of this flexibility is limited lor controlled by the axial length of the flange I4.`

The tube I0 extends within the bore 32 through the shoulder 28 of the body member 20. The clearance between the tube I0 and the adjacent wall of the bore 32 is larger than that between the flange I4 and the bore 22 whereby the flange I4 pilots the tube I0 within the body member 20. However, the clearance between the tube I0 and y. the adjacent wall of the boreV 32 is sufficiently small to inhibit extrusion of the washer 30 therethrough.

In operation, the hydraulic pressure within the tube I0 acts behind the washer to urge the washer against the flange I4 thereby further compressing the washer 30 between the bore 22 and the tube I0 whereby the washer 30 provides an effective seal. The ferrule l2 has been disclosed as rigidly secured to the tube I0 whereby the nut 26 positively prevents separation of the tube and body member 2li-e. g. by the hydraulic pressure therein. However, if the body member 20 and the remote end of the tube are mounted against relative movement and the tube is substantially rigid, then the ferrule need not be secured to the tube III.

Figure 3 illustrates a modification generally similar to that of Figures '1 2 `but permitting greater flexibility between vthe tube' 40 and the body member 42 to which the tube is to be coupled. In Figure 3, the body member is provided with a bore 44 having a shoulder 46 provided with a concave spherical surface 41 facing the open end of the bore through which the tube 4I) is received.

a curvature similar tothe external spherical surface52 of the ferrule 50. The nut 56 is adapted to be threaded on the member 42 with its internal spherical surface 58` engaging the external spherical surface 52 of the ferrule 50 thereby securing the tube 40 to the member 42. A washer 62l of resilient rubber-like material is disposed in the annular space 64 between the inner end of the ferrule 5D and the adjacent spherical surface 41 of the shoulder 46. vAs in the modification of. Figures 1-2, the washer 62 has free externaland internal diameters respectively larger and smaller 1 than the outer and inner diameters of the annular space 64 occupied thereby. The nut 56l is threaded along the member 42 until it engages the en d 60 of the member 42; at which time the center of curvature of its internal rspherical surface 58 and the external surface 52 of the ferrule both coincide with the point 48.

The tube 40 extends inwardly to provide only a small clearance between the inner end of the tube 4U and the adjacent wall 'of the member 42 to restrain extrusion of the washer62 therethrough. Preferably, the clearance between the ferrule 5l and the adjacent spherical surface 41 is even smaller and corresponds to the clearance between the flange I4 and the bore 22 in Figures 1-2.

The construction of Figure 3 permits substantial misalinement of the tube 40 and the bore 44 l and, at the same time, insures an adequate seal. Thus, with the nut 56 engaging the end 6l, the annular space 64, between the inner end of the ferrule 5l! and the facing spherical surface 41 vof the shoulder 46, remains substantially unchanged with changes in the alinement of the tube 40 relative to the bore 44. That is, the annular space 64 does not substantially increase in size on one side and decrease in size on the other side as the alinement of the tube 40 is changed. Accordingly, the alinement of the tube 40 has ,little or no influence on the effectiveness of the seal. At this point, it should be noted that the nut surface 58 need not be spherical. For example, this surface may be conical and still permit pivotal movement of the tube I0 about the center 4l without distorting the annular space 64. Also. at its area engageable' with the nut 56, the ferrule maybe provided with an annular insert having good wearing properties.

In Figure 3, as in Figures 1-2, vibrations of the body member are transmitted to the tube primarily through the securing nut and ferrule, whereby the resilient rubber-like washer 62 at most transmits only a small proportion of these vibrations. Also,as in Figures 1-2, the ferrule 50 need not be rigidly secured to the tube 40.

Figure 4 illustrates a modification of Figures 1 and 2 permitting slightly more flexibility than that present in Figures 1-2 without the spherical surfaces of Figure 3. Figure 4 is similar to Figures 1-2 except a second washer 10 is provided and portions ofv Figure 4, corresponding to portions of Figures 1-2, have been designated by tube I0', tends to vibrationally isolate the tube I0' from the member 20.

While we have described our invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding our invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. We aim in the appended claims to cover all such modifications.

We `claim as our invention:

l. A fluid-tight joint comprising a first tubular member, a second member vhaving a chamber within which said first member is received, an annular shoulder carried by said second member within said chamber and facing the open ond of said chamber through which said first member is received, a'collar disposed about and :3ecured to said first member within said chamber and spaced axially outwardly from said shoulder, said first*` member extending into said chamber beyond said collar, an annular washer of resilient rubber-like material disposed in the annular lspace about said first member between said collar and shoulder, the securement of said collar to said first member being independent of said washer, said washer having a free external d'afneter greater than that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of saii space engaged by said washer, the external diametcr of said collar being only slightly smailer than that of the adjacent wail of said chamber to prevent extrusion of said washer through the clearance between said collar and chamber wall by the fluid pressure behind said washer and means carried by said second member for retaining said collar within said chamber.

2. A fluid-tight joint comprising a first tubular member, a second member having a chamr ber within which said first member is receivel, an annular shoulder carried by said second member within said chamber and facing the. open end of said chamber through which said first member is received, a collar disposed about and secured to said first member within said Chamb r and spaced axially outwardly from said shoulder, an annular washer of resilient rubber-like matcrial disposed in th`e annular space about said first member between said collar and shoulder, the securement of said collar to said first meinber being independent of said washer, said washer having a free external diameter greater than that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially inner Wall of said space engaged by said Washer, said first member extending into sail chamber beyond said collar and its inner end having at least a small clearance with the adjacent wall of said chamber, said collar having an external diameter only slightly smailer than that of the adjacent wall of said chamber so that the clearance'therebetween is sufficiently small to prevent :extrusion of said washer therethrough by the fluid pressure behind said washer and` means carried by said second member for retaining said collar within said chamber'.

3. A fiuid-tight joint comprising'a first tubular member, a second member having a chamber Within which said first member is received, anannular shoulder carried by said second member within said chamber and facing the open end of said chamber through which said first member is received, an annular external flange secured to said first member within said chamber and spaced axially outwardly of said shoulder. said first member extending into said chamber beyond said flange, an annular washer of resilient rubber-like material disposed in the annular space about said tube between said flange and shoulder, the securement of said flange to said first member being independent of said washer, said washer having a free external di-4 ameter greater thanA that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially innery wall of said spaceengaged by said washer, and means carried by and adjustable relative to said second member for retaining said flange within said chamber.

4. A fiuid-tight -joint comprising a first tubular member, a second member having a chamber within which said first member is reczived, an

annular shoulder carried by said second member within said chamber and facing the open end of said chamber through which said first member is received, a collar disposed about and secured to said first member within said chamber and spaced axially outwardly of -said shoulder, an annular washer of resilient rubber-like material disposed in the annular space about said first member between said collar and shoulder, the ysecurement of said collar to said first member being independent of said washer, said washer having a free external diameter greater than.

that portion of the radially outer wall of said space engaged by sald washer and having a free internal' diameter -smaller than that portion of the radially inner wall of said space engaged by said Washer, the external diameter of said collar being only slightly smaller than that of the adjacent wall of said chamber to prevent extrusion of said washer through the clearance between v said collar and said chamber Wall by the fiuid pressure behind said washer,4 a second annular `washer disposed about said first member on the side of said flange remote from said first-mentioned annular washer, and annular means carried by said second member and engageabie with said second washer for retaining said collar within said chamber, said second washer being more yieldable than bothv said annular washer and said collar, but less yieldable than said first-mentioned washer.

5. A fluid-tight joint comprising a lfirst tubular member, a second member having a chamberwithin which said first member is received, an annular shoulder carried by said second member within said chamber, said shoulder having a concave spherical surface facing the open end of said chamber through which said rst member is received, a colla-r disposed about said first member Within said chamber, said collar having an external convex spherical surface on its side remote from said shoulder, and an annular washer of resilient rubber-like material disposed in the annular space about said rst member between said collar and shoulder, said washer having a free external diameter greater than that portion of the radially outer wall of said space engaged byfsjaid washer and having Va free internal vdiameter smaller :than thatflpor'tion of the radially inner wall ofsvaid spaceengagedjby; 5

e. lil fluid-tight joint temprame` e t niet; tuuular member, a secondmember :having 1a chamf ber within which said first member is received.,

an annular Ashoulder carried by Vsaid secondfmrem- '10 ber within said chamber, said shoulderhaving a member withinsaid chamber, said collar havingv an external convex spherical surface on its sidev remotev 'from said shoulderfa'n annular washer of resilient rubber-like material disposed inV the annular space about said first member/between free external diameter greater than that portion of the radially outer wall of said spaceengaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of said space engaged by said washer,

and'means carried by said second member for engagement with the convex spherical surface of said collar to retain said collar within said chamber.

7. A fiuid-tight joint comprising a first tubular member, a second member having a chamber within which said first member is received, an annular shoulder carried by said second member Within said chamber, said shoulder having a. concave spherical surface facing the open end of said chamber through which said first member is received, a collar disposed about said first member within said chamber, said collar having a substantially radial side facing said shoulder and an external convex spherical surface on its other side with a radius of curvature only slightly smaller than the radius of the spherical surface of said shoulder, and an annular washer of resilient rubber-like material disposed in the annular space about said first member between 4,-,

said collar and shoulder, said washer having a free external diameter greater than that portion of the radially outer wall of said space, engaged by said washer and having a free internal diameter smaller than that portion of the radially 50 inner wall of said space engaged by said washer.,

8. A lfiuid-tight joint comprising a. first tubular member, a second member having a chamber within which said first member is received, an

annular shoulder carried by said second member 515 within said chamber, said shoulder having a concave spherical surface facing the open end of said chamber through which said first member is received, a collar disposed about said first member within said chamber, said collar having a .60

substantially radial side facing said shoulder and an external convex spherical surface on its other side with a radius of curvature only slightly smaller than the radius of the spherical surface of said shoulder, an annular washer of resilient rubber-like material disposed in the annular space about said first member between said collar and shoulder, said washer having a free external diameter greater than that portion of the radially outer Wall of said space. engaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of said space engaged by said washer, and means carried by said second member for axially moving said collar against said washer until said .i spherical surfaces have a substantially common center.

9'.'A nuid`ught jouit comprising 'e mst tubuf` lar memb'ena second' member having a chamber within ,which said `first member vis received,4 A

an annular shoul'der'carried by said second mem-- to said first member within said chamber, said collar Ahaving af'substantially radialside facing saidv shoulder and an external' convex spherical surface onits other side with a radius of vcurvature only slightly smaller f than the radius' of vthe spherical surface of said shoulder, an annularwasher of resilient rubber-like material .disposed inthe 'annular space about said rst l member between said collar and shoulder, said y said collar and shoulder, said washer having 'a 20 washer having a free external diameter greater than that portion of the radially outer wall of said space, engaged by said washer and having a free internal diameter smaller than that portion of-the radially inner wall of said space engaged by said washer, and means carried by and adjustable relative to said second member for axially moving said collar against said washer until said spherical surfaces have a substantially common center, said means having an internal concave spherical surface similar to and engaging the convex spherical'surfa'ce of said collar.

10. A fluid-tight joint comprising a first tubular member; a second member having aA chamber within which said first member is received; an annular shoulder carried by said second membei' within said chamber; said shoulder facing the open end of said chamber through which said first member is received; a colla-r disposed about and secured to said first member within vsaid washer having a free external diameter greater than that portion. of the radially outer wall of said space engaged by said washer and having a free internal diameter small than that portion of the radially inner wall of said space engaged by said washer; atleast that portion of the material `of said second member forming w the radially outer wall of said annular space being of one piece, and means carried by said second member for retaining said collar within said chamber.

11. A duid-tight joint comprising a first tubular member; a second member having a chamber within which said first member isreceived;

.an annular shoulder carried by said second member within said chamber; said shoulder facing the open end of said chamber through which said first member is received; a collar disposed about and secured to said first member within said chamber and spaced axially outwardly lfrom said shoulder; said first member extending into said chamber beyond said collar; an annular washer of resilient rubber-like material disposed en- -tirely in the annular space, of said chamber.

about said rst member between said collar and shoulder; the securement of said collar to said rst member being independent of said washer;

said washer having afree external diameterv greater than that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of said spaced engaged by said washer; at least that portion of the material of said second member forming the radially outer wall of said annular space being of one piece; the external diameter of said collar being only slightly smalhr than that of the adjacent wall of said chamber to prevent extrusion of said washer through the clearance between said collar and chamber wall by the fluid pressure behind said washer; and means carried by said second member for retaining said collar within said chamber.

12. A fluid-tight joint comprising a first tubular member; a second member having a chamber Within which said first member is received; an annular shoulder carried by said second member within said chamber; said shoulder having a concave spherical surface facing the open end of said chamber through which said first member is received; a collar disposed about said rst member within said chamber; said first member eX-. tending into said chamber beyond said collar; and an annular washer of resilient rubber-like material disposed in the annular space about said first member between said collar and spherical shoulder surface; said washer having a free external diameter greater than that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of said space engaged by said Washer.

13. A fluid-tight joint comprising a first tubu lar member; a second member having a chamber within which said first member is received; an

annular shoulder carried by said second member within said chamber, said shoulder having a concave spherical surface facing the open end of said chamber vthrough which said first member i0 is received; a collar disposed about and secured to said first member within said chamber and having a substantially radially disposed surface facing inwardly into said chamber and an external convex spherical surface extending toward the open end of said chamber from said radially disposed surface, said rst member extending into said chamber beyond its said collar; an annular washerof resilient rubber like material disposed in the annular space about said rst member between the radially disposed surface of said collar and the concave spherical surface of said shoulder, said washer having a free external diameter larger than that portion of the radially outer wall of said space engaged by said washer and having a free internal diameter smaller than that portion of the radially inner wall of said space engaged by said washer; and means carried by said second memberI for retaining said collar within said chamber with its convex spherical surface at least partially overlapped by the concave spherical surface of said shoulder. 1 FRANCIS J. WIEGAND.

DUIS W. MEADOR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Great Britain Feb. 3. 1927 

